(function () {
    // Shortcuts
    var C = CryptoJS;
    var C_lib = C.lib;
    var WordArray = C_lib.WordArray;
    var C_enc = C.enc;

    /**
     * Base64url encoding strategy.
     */
    var Base64url = C_enc.Base64url = {
        /**
         * Converts a word array to a Base64url string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @param {boolean} urlSafe Whether to use url safe
         *
         * @return {string} The Base64url string.
         *
         * @static
         *
         * @example
         *
         *     var base64String = CryptoJS.enc.Base64url.stringify(wordArray);
         */
        stringify: function (wordArray, urlSafe) {
            if (urlSafe === undefined) {
                urlSafe = true
            }
            // Shortcuts
            var words = wordArray.words;
            var sigBytes = wordArray.sigBytes;
            var map = urlSafe ? this._safe_map : this._map;

            // Clamp excess bits
            wordArray.clamp();

            // Convert
            var base64Chars = [];
            for (var i = 0; i < sigBytes; i += 3) {
                var byte1 = (words[i >>> 2]       >>> (24 - (i % 4) * 8))       & 0xff;
                var byte2 = (words[(i + 1) >>> 2] >>> (24 - ((i + 1) % 4) * 8)) & 0xff;
                var byte3 = (words[(i + 2) >>> 2] >>> (24 - ((i + 2) % 4) * 8)) & 0xff;

                var triplet = (byte1 << 16) | (byte2 << 8) | byte3;

                for (var j = 0; (j < 4) && (i + j * 0.75 < sigBytes); j++) {
                    base64Chars.push(map.charAt((triplet >>> (6 * (3 - j))) & 0x3f));
                }
            }

            // Add padding
            var paddingChar = map.charAt(64);
            if (paddingChar) {
                while (base64Chars.length % 4) {
                    base64Chars.push(paddingChar);
                }
            }

            return base64Chars.join('');
        },

        /**
         * Converts a Base64url string to a word array.
         *
         * @param {string} base64Str The Base64url string.
         *
         * @param {boolean} urlSafe Whether to use url safe
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Base64url.parse(base64String);
         */
        parse: function (base64Str, urlSafe) {
            if (urlSafe === undefined) {
                urlSafe = true
            }

            // Shortcuts
            var base64StrLength = base64Str.length;
            var map = urlSafe ? this._safe_map : this._map;
            var reverseMap = this._reverseMap;

            if (!reverseMap) {
                reverseMap = this._reverseMap = [];
                for (var j = 0; j < map.length; j++) {
                    reverseMap[map.charCodeAt(j)] = j;
                }
            }

            // Ignore padding
            var paddingChar = map.charAt(64);
            if (paddingChar) {
                var paddingIndex = base64Str.indexOf(paddingChar);
                if (paddingIndex !== -1) {
                    base64StrLength = paddingIndex;
                }
            }

            // Convert
            return parseLoop(base64Str, base64StrLength, reverseMap);

        },

        _map: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
        _safe_map: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_',
    };

    function parseLoop(base64Str, base64StrLength, reverseMap) {
        var words = [];
        var nBytes = 0;
        for (var i = 0; i < base64StrLength; i++) {
            if (i % 4) {
                var bits1 = reverseMap[base64Str.charCodeAt(i - 1)] << ((i % 4) * 2);
                var bits2 = reverseMap[base64Str.charCodeAt(i)] >>> (6 - (i % 4) * 2);
                var bitsCombined = bits1 | bits2;
                words[nBytes >>> 2] |= bitsCombined << (24 - (nBytes % 4) * 8);
                nBytes++;
            }
        }
        return WordArray.create(words, nBytes);
    }
}());
